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Posted to commits@logging.apache.org by rp...@apache.org on 2015/08/09 18:17:03 UTC

[07/11] logging-log4j2 git commit: LOG4J2-599 log4j lambda support - Renamed LambdaLogger to Logger2 - Renamed ExtendedLambdaLogger to ExtendedLogger2 - Renamed LogManager#getLambdaLogger methods to #getLogger2 - Introduced custom functional interface Su

LOG4J2-599 log4j lambda support
- Renamed LambdaLogger to Logger2
- Renamed ExtendedLambdaLogger to ExtendedLogger2
- Renamed LogManager#getLambdaLogger methods to #getLogger2
- Introduced custom functional interface Supplier and replaced
Callable<?> in Logger2 with Supplier<?>
- LambdaSupport changes for Supplier instead of Callable
- Introduced custom functional interface MessageSupplier for lambda
expressions that create Message objects directly
- documentation updates
- initial Logger2Test (more tests to follow) 

Project: http://git-wip-us.apache.org/repos/asf/logging-log4j2/repo
Commit: http://git-wip-us.apache.org/repos/asf/logging-log4j2/commit/12be6d86
Tree: http://git-wip-us.apache.org/repos/asf/logging-log4j2/tree/12be6d86
Diff: http://git-wip-us.apache.org/repos/asf/logging-log4j2/diff/12be6d86

Branch: refs/heads/master
Commit: 12be6d867031c4579ccca856359d04482145e01e
Parents: 63a325d
Author: rpopma <rp...@apache.org>
Authored: Sun Aug 9 23:53:39 2015 +0900
Committer: rpopma <rp...@apache.org>
Committed: Sun Aug 9 23:53:39 2015 +0900

----------------------------------------------------------------------
 .../org/apache/logging/log4j/LambdaLogger.java  | 429 -----------
 .../org/apache/logging/log4j/LogManager.java    |  72 +-
 .../java/org/apache/logging/log4j/Logger2.java  | 738 +++++++++++++++++++
 .../logging/log4j/spi/AbstractLogger.java       | 270 +++++--
 .../logging/log4j/spi/ExtendedLambdaLogger.java |  56 --
 .../logging/log4j/spi/ExtendedLogger2.java      |  68 ++
 .../apache/logging/log4j/util/LambdaUtil.java   |  24 +-
 .../logging/log4j/util/MessageSupplier.java     |  40 +
 .../org/apache/logging/log4j/util/Supplier.java |  40 +
 .../org/apache/logging/log4j/Logger2Test.java   | 190 +++++
 .../logging/log4j/util/LambdaUtilTest.java      |  95 ++-
 src/site/xdoc/manual/api.xml                    |   6 +-
 12 files changed, 1409 insertions(+), 619 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/12be6d86/log4j-api/src/main/java/org/apache/logging/log4j/LambdaLogger.java
----------------------------------------------------------------------
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/LambdaLogger.java b/log4j-api/src/main/java/org/apache/logging/log4j/LambdaLogger.java
deleted file mode 100644
index 84a3fef..0000000
--- a/log4j-api/src/main/java/org/apache/logging/log4j/LambdaLogger.java
+++ /dev/null
@@ -1,429 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache license, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the license for the specific language governing permissions and
- * limitations under the license.
- */
-
-package org.apache.logging.log4j;
-
-import java.util.concurrent.Callable;
-
-/**
- * Extends the {@code Logger} interface with support for lambda expressions.
- * <p>
- * This logger allows client code to lazily log messages without explicitly checking if the requested log level is
- * enabled. For example, previously one would write:
- * 
- * <pre>
- * // pre-Java 8 style optimization: explicitly check the log level
- * // to make sure the expensiveOperation() method is only called if necessary
- * Logger logger = LogManager.getLogger();
- * if (logger.isTraceEnabled()) {
- *     logger.trace(&quot;Some long-running operation returned {}&quot;, expensiveOperation());
- * }
- * </pre>
- * <p>
- * With Java 8 and the {@code LambdaLogger} interface, one can achieve the same effect by using a lambda expression:
- * 
- * <pre>
- * // Java-8 style optimization: no need to explicitly check the log level:
- * // the lambda expression is not evaluated if the TRACE level is not enabled
- * LambdaLogger logger = LogManager.getLambdaLogger();
- * logger.trace(&quot;Some long-running operation returned {}&quot;, () -&gt; expensiveOperation());
- * </pre>
- */
-public interface LambdaLogger extends Logger {
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void debug(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) including the
-     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack trace.
-     */
-    void debug(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level with
-     * the specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void debug(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) with the
-     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void debug(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
-     * DEBUG} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void debug(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
-     * DEBUG} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void debug(String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void error(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) including the
-     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack trace.
-     */
-    void error(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level with
-     * the specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void error(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) with the
-     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void error(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
-     * ERROR} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void error(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
-     * ERROR} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void error(String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void fatal(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) including the
-     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack trace.
-     */
-    void fatal(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level with
-     * the specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void fatal(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) with the
-     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void fatal(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
-     * FATAL} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void fatal(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
-     * FATAL} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void fatal(String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void info(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) including the
-     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack trace.
-     */
-    void info(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level with the
-     * specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void info(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) with the
-     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void info(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
-     * INFO} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void info(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
-     * INFO} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void info(String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the specified level.
-     *
-     * @param level the logging level
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void log(Level level, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the specified level) including the stack log of
-     * the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param level the logging level
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack log.
-     */
-    void log(Level level, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker.
-     *
-     * @param level the logging level
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void log(Level level, Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker and
-     * including the stack log of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param level the logging level
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void log(Level level, Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
-     *
-     * @param level the logging level
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void log(Level level, Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
-     *
-     * @param level the logging level
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void log(Level level, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void trace(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) including the
-     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack trace.
-     */
-    void trace(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level with
-     * the specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void trace(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) with the
-     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void trace(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
-     * TRACE} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void trace(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
-     * TRACE} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void trace(String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void warn(Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) including the
-     * stack warn of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t the exception to log, including its stack warn.
-     */
-    void warn(Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level with the
-     * specified Marker.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     */
-    void warn(Marker marker, Callable<?> msgSupplier);
-
-    /**
-     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) with the
-     * specified Marker and including the stack warn of the {@link Throwable} <code>t</code> passed as parameter.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param msgSupplier A function, which when called, produces the desired log message.
-     * @param t A Throwable or null.
-     */
-    void warn(Marker marker, Callable<?> msgSupplier, Throwable t);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
-     * WARN} level.
-     *
-     * @param marker the marker data specific to this log statement
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void warn(Marker marker, String message, Callable<?>... paramSuppliers);
-
-    /**
-     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
-     * WARN} level.
-     *
-     * @param message the message to log; the format depends on the message factory.
-     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
-     */
-    void warn(String message, Callable<?>... paramSuppliers);
-
-}

http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/12be6d86/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
----------------------------------------------------------------------
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java b/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
index f4aa848..196aa9f 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
@@ -416,12 +416,13 @@ public class LogManager {
     }
 
     /**
-     * Returns a LambdaLogger with the name of the calling class.
-     * @return The LambdaLogger for the calling class.
+     * Returns a Logger2 with the name of the calling class.
+     * @return The Logger2 for the calling class.
      * @throws UnsupportedOperationException if the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger() {
-        return (LambdaLogger) getLogger(ReflectionUtil.getCallerClass(2));
+    public static Logger2 getLogger2() {
+        return (Logger2) getLogger(ReflectionUtil.getCallerClass(2));
     }
     
     private static Class<?> callerClass(final Class<?> clazz) {
@@ -436,90 +437,97 @@ public class LogManager {
     }
 
     /**
-     * Returns a LambdaLogger using the fully qualified name of the Class as the Logger name.
+     * Returns a Logger2 using the fully qualified name of the Class as the Logger name.
      * @param clazz The Class whose name should be used as the Logger name. If null it will default to the calling
      *              class.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code clazz} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final Class<?> clazz) {
+    public static Logger2 getLogger2(final Class<?> clazz) {
         final Class<?> cls = callerClass(clazz);
-        return (LambdaLogger) getContext(cls.getClassLoader(), false).getLogger(cls.getName());
+        return (Logger2) getContext(cls.getClassLoader(), false).getLogger(cls.getName());
     }
 
     /**
-     * Returns a LambdaLogger using the fully qualified name of the Class as the Logger name.
+     * Returns a Logger2 using the fully qualified name of the Class as the Logger name.
      * @param clazz The Class whose name should be used as the Logger name. If null it will default to the calling
      *              class.
      * @param messageFactory The message factory is used only when creating a logger, subsequent use does not change
      *                       the logger but will log a warning if mismatched.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code clazz} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final Class<?> clazz, final MessageFactory messageFactory) {
+    public static Logger2 getLogger2(final Class<?> clazz, final MessageFactory messageFactory) {
         final Class<?> cls = callerClass(clazz);
-        return (LambdaLogger) getContext(cls.getClassLoader(), false).getLogger(cls.getName(), messageFactory);
+        return (Logger2) getContext(cls.getClassLoader(), false).getLogger(cls.getName(), messageFactory);
     }
 
     /**
-     * Returns a LambdaLogger with the name of the calling class.
+     * Returns a Logger2 with the name of the calling class.
      * @param messageFactory The message factory is used only when creating a logger, subsequent use does not change
      *                       the logger but will log a warning if mismatched.
-     * @return The LambdaLogger for the calling class.
+     * @return The Logger2 for the calling class.
      * @throws UnsupportedOperationException if the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final MessageFactory messageFactory) {
-        return (LambdaLogger) getLogger(ReflectionUtil.getCallerClass(2), messageFactory);
+    public static Logger2 getLogger2(final MessageFactory messageFactory) {
+        return (Logger2) getLogger(ReflectionUtil.getCallerClass(2), messageFactory);
     }
 
     /**
-     * Returns a LambdaLogger using the fully qualified class name of the value as the Logger name.
+     * Returns a Logger2 using the fully qualified class name of the value as the Logger name.
      * @param value The value whose class name should be used as the Logger name. If null the name of the calling
      *              class will be used as the logger name.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code value} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final Object value) {
-        return (LambdaLogger) getLogger(value != null ? value.getClass() : ReflectionUtil.getCallerClass(2));
+    public static Logger2 getLogger2(final Object value) {
+        return (Logger2) getLogger(value != null ? value.getClass() : ReflectionUtil.getCallerClass(2));
     }
 
     /**
-     * Returns a LambdaLogger using the fully qualified class name of the value as the Logger name.
+     * Returns a Logger2 using the fully qualified class name of the value as the Logger name.
      * @param value The value whose class name should be used as the Logger name. If null the name of the calling
      *              class will be used as the logger name.
      * @param messageFactory The message factory is used only when creating a logger, subsequent use does not change
      *                       the logger but will log a warning if mismatched.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code value} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final Object value, final MessageFactory messageFactory) {
-        return (LambdaLogger) getLogger(value != null ? value.getClass() : ReflectionUtil.getCallerClass(2),
+    public static Logger2 getLogger2(final Object value, final MessageFactory messageFactory) {
+        return (Logger2) getLogger(value != null ? value.getClass() : ReflectionUtil.getCallerClass(2),
                 messageFactory);
     }
 
     /**
-     * Returns a LambdaLogger with the specified name.
+     * Returns a Logger2 with the specified name.
      *
      * @param name The logger name. If null the name of the calling class will be used.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code name} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final String name) {
-        return (LambdaLogger) (name != null ? getContext(false).getLogger(name) : getLogger(
+    public static Logger2 getLogger2(final String name) {
+        return (Logger2) (name != null ? getContext(false).getLogger(name) : getLogger(
                 ReflectionUtil.getCallerClass(2)));
     }
 
     /**
-     * Returns a LambdaLogger with the specified name.
+     * Returns a Logger2 with the specified name.
      *
      * @param name The logger name. If null the name of the calling class will be used.
      * @param messageFactory The message factory is used only when creating a logger, subsequent use does not change
      *                       the logger but will log a warning if mismatched.
-     * @return The LambdaLogger.
+     * @return The Logger2.
      * @throws UnsupportedOperationException if {@code name} is {@code null} and the calling class cannot be determined.
+     * @since log4j-2.4
      */
-    public static LambdaLogger getLambdaLogger(final String name, final MessageFactory messageFactory) {
-        return (LambdaLogger) (name != null ? getContext(false).getLogger(name, messageFactory) : getLogger(
+    public static Logger2 getLogger2(final String name, final MessageFactory messageFactory) {
+        return (Logger2) (name != null ? getContext(false).getLogger(name, messageFactory) : getLogger(
             ReflectionUtil.getCallerClass(2), messageFactory));
     }
 

http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/12be6d86/log4j-api/src/main/java/org/apache/logging/log4j/Logger2.java
----------------------------------------------------------------------
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/Logger2.java b/log4j-api/src/main/java/org/apache/logging/log4j/Logger2.java
new file mode 100644
index 0000000..4315841
--- /dev/null
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/Logger2.java
@@ -0,0 +1,738 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache license, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the license for the specific language governing permissions and
+ * limitations under the license.
+ */
+
+package org.apache.logging.log4j;
+
+import org.apache.logging.log4j.message.MessageFactory;
+import org.apache.logging.log4j.util.MessageSupplier;
+import org.apache.logging.log4j.util.Supplier;
+
+/**
+ * Extends the {@code Logger} interface with support for lambda expressions.
+ * <p>
+ * This logger allows client code to lazily log messages without explicitly checking if the requested log level is
+ * enabled. For example, previously one would write:
+ * 
+ * <pre>
+ * // pre-Java 8 style optimization: explicitly check the log level
+ * // to make sure the expensiveOperation() method is only called if necessary
+ * Logger logger = LogManager.getLogger();
+ * if (logger.isTraceEnabled()) {
+ *     logger.trace(&quot;Some long-running operation returned {}&quot;, expensiveOperation());
+ * }
+ * </pre>
+ * <p>
+ * With Java 8 and the {@code Logger2} interface, one can achieve the same effect by using a lambda expression:
+ * 
+ * <pre>
+ * // Java-8 style optimization: no need to explicitly check the log level:
+ * // the lambda expression is not evaluated if the TRACE level is not enabled
+ * Logger2 logger = LogManager.getLogger2();
+ * logger.trace(&quot;Some long-running operation returned {}&quot;, () -&gt; expensiveOperation());
+ * </pre>
+ * 
+ * @since log4j-2.4
+ */
+public interface Logger2 extends Logger {
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void debug(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack trace.
+     */
+    void debug(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level with
+     * the specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void debug(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void debug(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level with
+     * the specified Marker. The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the
+     * {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void debug(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter. The
+     * {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void debug(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level. The
+     * {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void debug(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter. The {@code MessageSupplier} may or may
+     * not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack trace.
+     */
+    void debug(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
+     * DEBUG} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void debug(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
+     * DEBUG} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void debug(String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void error(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack trace.
+     */
+    void error(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level with
+     * the specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void error(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void error(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
+     * ERROR} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void error(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void error(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void error(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void error(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack trace.
+     */
+    void error(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
+     * ERROR} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void error(String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void fatal(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack trace.
+     */
+    void fatal(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level with
+     * the specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void fatal(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void fatal(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
+     * FATAL} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void fatal(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void fatal(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void fatal(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void fatal(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack trace.
+     */
+    void fatal(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
+     * FATAL} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void fatal(String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void info(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack trace.
+     */
+    void info(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level with the
+     * specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void info(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void info(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
+     * INFO} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void info(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void info(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void info(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void info(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack trace.
+     */
+    void info(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
+     * INFO} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void info(String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the specified level.
+     *
+     * @param level the logging level
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void log(Level level, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the specified level) including the stack log of
+     * the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param level the logging level
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack log.
+     */
+    void log(Level level, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker.
+     *
+     * @param level the logging level
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void log(Level level, Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker and
+     * including the stack log of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param level the logging level
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void log(Level level, Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
+     *
+     * @param level the logging level
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void log(Level level, Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the specified level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param level the logging level
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void log(Level level, Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the specified level) with the
+     * specified Marker and including the stack log of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param level the logging level
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void log(Level level, Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the specified level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param level the logging level
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void log(Level level, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the specified level) including the
+     * stack log of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param level the logging level
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack log.
+     */
+    void log(Level level, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
+     *
+     * @param level the logging level
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void log(Level level, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void trace(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack trace.
+     */
+    void trace(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level with
+     * the specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void trace(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void trace(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
+     * TRACE} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void trace(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void trace(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) with the
+     * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void trace(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void trace(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) including the
+     * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack trace.
+     */
+    void trace(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
+     * TRACE} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void trace(String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void warn(Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) including the
+     * stack warn of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t the exception to log, including its stack warn.
+     */
+    void warn(Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level with the
+     * specified Marker.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     */
+    void warn(Marker marker, Supplier<?> msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) with the
+     * specified Marker and including the stack warn of the {@link Throwable} <code>t</code> passed as parameter.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
+     *            message factory.
+     * @param t A Throwable or null.
+     */
+    void warn(Marker marker, Supplier<?> msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
+     * WARN} level.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void warn(Marker marker, String message, Supplier<?>... paramSuppliers);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level with
+     * the specified Marker. 
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void warn(Marker marker, MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) with the
+     * specified Marker and including the stack warn of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param marker the marker data specific to this log statement
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t A Throwable or null.
+     */
+    void warn(Marker marker, MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     */
+    void warn(MessageSupplier msgSupplier);
+
+    /**
+     * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) including the
+     * stack warn of the {@link Throwable} <code>t</code> passed as parameter.
+     * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
+     *
+     * @param msgSupplier A function, which when called, produces the desired log message.
+     * @param t the exception to log, including its stack warn.
+     */
+    void warn(MessageSupplier msgSupplier, Throwable t);
+
+    /**
+     * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
+     * WARN} level.
+     *
+     * @param message the message to log; the format depends on the message factory.
+     * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
+     */
+    void warn(String message, Supplier<?>... paramSuppliers);
+
+}